A comparison of supercapacitor and high-power lithium batteries

This paper reports and analyses experimental results showing the performances of two state-of-the art, commercially available storage systems, i.e. a supercapacitor (SC) and a super-high power lithium battery. These devices are often subject of comparison; the aim of the article is to explore their performances and to provide guidance in choosing the right device according to the application. The results are expressed mainly in terms of specific power and charge/discharge efficiency as a function of the wanted discharge time; they show that, very high power lithium batteries are a Wry useful solution for applications where high energy density is requested and peak powers can be delivered without additional storage systems; their limits consists of the limited cycle life and a sharp system temperature rise in these operative conditions. Supercapacitors, unlike, show high power density with a cycle life two orders of magnitude higher than high power lithium batteries. Their limit lies in the energy density that is up to two orders of magnitude smaller than high power lithium batteries. Further investigations are conducted to verify the performances and efficiency of very high power lithium batteries in cycles of high power charge and discharge very close to those typical for supercapacitors.